Box sash windows in cavity walls

[Marischal Ellis]

We do this all the time north of the border or at least we used to. I am sure someone will come along with a full understanding......I am out of date now. but it would have been normal, anything else would have been wrong. Insulation messed everything up.new rethink now essential.
Best wishes to all.

 

[Ollie78]

Turns out to be pretty straightforward. Building Control happy for us to make up the check reveal using the cavity closers, or to do a block work return and simply foam up to the cavity closer or block work to hold them in place.

I would certainly do a block work return if you can. Cavity closers are the flimsiest rubbish ever. You can wedge and foam nicely into a proper return.

Ollie